Metcalfe on Ethernetís lessons, unsung heros

"There's an army of unsung engineers who helped invent Ethernet," says Bob Metcalfe, taking a long drag on his cigarette as he ruminates about the now ubiquitous network technology he described in a memo to colleagues at Xerox PARC on May 22, 1973.

Another drag, another name. Ron Crane, another Stanford grad student.
Metcalfe hired Crane for his Xerox team and later recruited him as a
hardware guru at 3Com, the company Metcalfe built to take Ethernet to
the market. “Crane led the design of all our early Ethernet products and
helped develop the IEEE standard” along with many others, Metcalfe
recalled. “The list starts getting long now,” he said.

Click on image to enlarge.

David Boggs, Ron Crane and Robert Metcalfe

Indeed,
hundreds of engineers have helped drive various flavors of Ethernet
through standards bodies, into products and out to the market. It all
began when PARC hired Metcalfe to find a way to network the Alto
microcomputers it built in the days before the PC. He wound up unseating
another engineer who previously had that charter, Charles Simonyi.

In
a twist of fate, “when I came Simonyi switched to developing a text
editor which over time evolved into Microsoft Word and made him a
billionaire who has since visited the International Space Station
twice,” said Metcalfe, taking another long draw on his cigarette.

In
his 1973 memo, Metcalfe outlined his thoughts on Ethernet. He conceived
a variation of the Aloha Network at the University of Hawaii he studied
as part of a Harvard doctoral thesis. It sported two innovations — an
algorithm that uses data collisions to minimize interference and the
flexibility to run over any medium, even the mythical Ether for which he
named it.

Click on image to enlarge.

Bob Metcalfe at PARC 1973

There
were plenty of fights along the way in IEEE standards groups with
giants like IBM and even General Motors who tried to define their own
networks--and fights in the market trying to establish those
technologies and others.

In the end, Metcalfe’s concepts became
the basis for local area networks. Ethernet won in part “due to the
sincerity of our efforts,” as opposed to the motivations of other
proposals trying to protect legacy businesses, Metcalfe claims.

Perhaps
more importantly, “Ethernet understands its role in the comms
hierarchy, it was a Layer 1-2 protocol and didn’t try to do more than
that,” he said. “As a result it is simpler and cheaper than the
alternatives because it only did want it needed and not more,” he added.

Ultimately
Ethernet was adopted as the basis for Wi-Fi and a wide range of nets
that now span everything from industrial controls to optical telco core
networks where it is replacing Sonet. It has evolved from 3 Mbits/s to
100 Gbits/s. Last year, vendors shipped 1.2 billion Ethernet
connections, 800 million of them wireless ones, according to
International Data Corp.

“It’s not even close to the same
technology — CSMA/CD [Carrier sense multiple access with collision
detection, one of Metcalfe’s early innovations] isn’t even in it
anymore, but the name is used to embody a bigger idea,” Metcalfe said.
“It could be the packet format or the business model of a de jure
standard with fierce competition and backward compatibility -- that
business model is I think what people mean by Ethernet, today,” he said.

Last year, Metcalfe took up a new job as Professor of Innovation at the University of Texas in Austin.

“My
mission is to help make Austin a better Silicon Valley, and the core of
that is an engineering school where I’m focused on helping engineers
who want to start companies,” said Metcalfe. “If you are interested in
starting a company, it’s my job to show you how to do it,” he said.

We asked if there are any unsung up-and-coming engineers he wanted to name.

“I am rooting for them all. There are plenty of people who will discourage them,” he said taking a last pull on his cigarette.

Although Metcalfe said it, I'm afraid the point gets lost in translation, almost always. What survived of Ethernet are really only two things: the name itself, and the format of the basic frame. That's it! In fact, there are more fancy IEEE variants of that basic frame now, still using the Ethernetr name.
Ethernet borrowed from other concepts, to keep itself viable. As speed increased, Ethernet dropped the shared bus medium and CSMA/CD protocol and adopted the rapid frame switching and full duplex links of ATM. (CSMA/CD is still there, but if used at all, it's only for a short point-to-point hop between one host and one switch port. Hardly what it was designed for!)
For the really fast interfaces, it adopted the optical transceivers of SONET.
And as Metcalfe said, it stayed strictly at layer 1 and 2, letting Internet Protocol (IP) take care of global routing between local networks. Where for example, ATM had its own global addressing and routing mechanisms, vying for the same roles as IP routing.
I think that the success of IP and packet switching, and the way Ethernet adopted techniques from other layer 1 and 2 network designs (the good ideas, leaving the not-so-good ideas behind), is what truly kept the Ethernet name alive.
It comes down to this: Ethernet, through all of its transformations, has always been "friendly to Internet Protocols." Much as SONET was friendly to ATM. So the true success story here is the way packet switching has pretty much come to dominate communications, taking over what used to be only circuit-switched networks or even virtual circuit networks. Ethernet and IP have been riding that packet switching wave together.

So via email, Bob Metcalfe tells me:
"THANKS! for your interview of me, which is great, except for one thing: I DO NOT SMOKE AND NEVER HAVE."
My mistake: The interview was done as a telecon and I thought I heard the sounds of Bob smoking and imagined the smoke, etc. My apologies!